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<H1 id="MPI_Group_translate_ranks">MPI_Group_translate_ranks</H1>
Translates the ranks of processes in one group to those in another group 
<H2>Synopsis</H2>
<PRE>
</PRE>
<PRE>
int MPI_Group_translate_ranks(MPI_Group group1, int n, const int ranks1[],
                              MPI_Group group2, int ranks2[])
</PRE>

<P>
<H2>Input Parameters</H2>
<DL>
<DT><B>group1 </B> <DD> group1 (handle)

<DT><B>n </B> <DD> number of ranks in ranks1 and ranks2 arrays (integer)

<DT><B>ranks1 </B> <DD> array of zero or more valid ranks in group1 (integer)

<DT><B>group2 </B> <DD> group2 (handle)
</DL>
<P>
<H2>Output Parameters</H2>
<DL>
<DT><B>ranks2 </B> <DD> array of corresponding ranks in group2, MPI_UNDEFINED when no correspondence exists. (integer)
</DL>
<P>
As a special case (see the MPI-2 errata), if the input rank is
<tt>MPI_PROC_NULL</tt>, <tt>MPI_PROC_NULL</tt> is given as the output rank.
<P>
<H2>Thread and Interrupt Safety</H2>
<P>
This routine is thread-safe.  This means that this routine may be
safely used by multiple threads without the need for any user-provided
thread locks.  However, the routine is not interrupt safe.  Typically,
this is due to the use of memory allocation routines such as <tt>malloc
</tt>or other non-MPICH runtime routines that are themselves not interrupt-safe.
<P>
<H2>Notes for Fortran</H2>
All MPI routines in Fortran (except for <tt>MPI_WTIME</tt> and <tt>MPI_WTICK</tt>) have
an additional argument <tt>ierr</tt> at the end of the argument list.  <tt>ierr
</tt>is an integer and has the same meaning as the return value of the routine
in C.  In Fortran, MPI routines are subroutines, and are invoked with the
<tt>call</tt> statement.
<P>
All MPI objects (e.g., <tt>MPI_Datatype</tt>, <tt>MPI_Comm</tt>) are of type <tt>INTEGER
</tt>in Fortran.
<P>
<H2>Errors</H2>
<P>
All MPI routines (except <tt>MPI_Wtime</tt> and <tt>MPI_Wtick</tt>) return an error value;
C routines as the value of the function and Fortran routines in the last
argument.  Before the value is returned, the current MPI error handler is
called.  By default, this error handler aborts the MPI job.  The error handler
may be changed with <tt>MPI_Comm_set_errhandler</tt> (for communicators),
<tt>MPI_File_set_errhandler</tt> (for files), and <tt>MPI_Win_set_errhandler</tt> (for
RMA windows).  The MPI-1 routine <tt>MPI_Errhandler_set</tt> may be used but
its use is deprecated.  The predefined error handler
<tt>MPI_ERRORS_RETURN</tt> may be used to cause error values to be returned.
Note that MPI does <em>not</em> guarantee that an MPI program can continue past
an error; however, MPI implementations will attempt to continue whenever
possible.
<P>
<DL>
<DT><B>MPI_SUCCESS </B> <DD> No error; MPI routine completed successfully.
</DL>
<DL>
<DT><B>MPI_ERR_ARG </B> <DD> Invalid argument.  Some argument is invalid and is not
identified by a specific error class (e.g., <tt>MPI_ERR_RANK</tt>).
</DL>
<DL>
<DT><B>MPI_ERR_GROUP </B> <DD> Null or invalid group passed to function.  
</DL>
<DL>
<DT><B>MPI_ERR_OTHER </B> <DD> Other error; use <tt>MPI_Error_string</tt> to get more information
about this error code. 
</DL>
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